L6925D STMICROELECTRONICS | Alldatasheet

Document overview

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Technical content

■ 2.7V TO 5.5V BATTERY INPUT RANGE ■ HIGH EFFICIENCY: UP TO 95% ■ INTERNAL SYNCHRONOUS SWITCH ■ NO EXTERNAL SCHOTTKY REQUIRED ■ EXTREMELY LOW QUIESCENT CURRENT ■ 800mA MAX OUTPUT CURRENT ■ ADJUSTABLE OUTPUT VOLTAGE FROM 0.6V ■ LOW DROP-OUT OPERATION: UP TO100% DUTY CYCLE ■ SELECTABLE LOW NOISE/LOW CONSUMPTION MODE AT LIGHT LOAD ■ LOW BATTERY INPUT ■ LOW BATTERY OUTPUT ■ ±1% OUTPUT VOLTAGE ACCURACY ■ CURRENT-MODE CONTROL ■ 600kHz SWITCHING FREQUENCY ■ EXTERNALLY SYNCHRONIZABLE FROM 500kHz TO 1.4MHz ■ OVP ■ SHORT CIRCUIT PROTECTION

APPLICATIONS

■ BATTERY-POWERED EQUIPMENTS ■ PORTABLE INSTRUMENTS ■ CELLULAR PHONES ■ PDAs AND HAND HELD TERMINALS ■ DSC ■ GPS

DESCRIPTION

The device is dc-dc monolithic regulator specifically designed to provide extremely high efficiency. The device has on UVLO set at 2.7V cause it is part- icurarly thought for single Li-ion cell applications. Output voltage can be selected by an external divider down to 0.6V. Duty Cycle can saturate to 100% al- lowing low drop-out operation. The device is based on a 600kHz fixed-frequency, current mode-architec- ture. Low Consumption Mode operation can be se- lected at light load conditions, allowing switching losses to be reduced. L6925D is externally synchro- nizable with a clock which makes it useful in noise- sensitive applications. LBI pin can be used to have a LBO signal when the Battery voltage is lower than a preset value. Other features like, Overvoltage protec- tion, Shortcircuit protection and Thermal Shutdown (150°C) are also present. MSOP8 ORDERING NUMBERS: L6925D (Tube) L6925013TR (Tape & Reel) HIGH EFFICIENCY MONOLITHIC SYNCHRONOUS STEP DOWN REGULATOR APPLICATION TEST CIRCUIT L 6.8mHSYNC LX VFB 10mF 6.3V 220pF 10mF 6.3V 200K 600K 100K 100K VIN=2.7V to 5.5V VOUT =1.8V VCC LBI COMP GND LBO D01IN1238B

Symbol Parameter Value Unit V6 Input voltage -0.3 to 6 V V5 Output switching voltage -1 to V CC V V1 Shutdown -0.3 to V CC V V3 Feedback voltage -0.3 to V CC V V2 Analog input voltage -0.3 to V CC V Ptot Power dissipation at Tamb=70°C0 . 4 5 W Tj Junction operating temperature range -40 to 150 °C Tstg Storage temperature range -65 to 150 °C LX Pin Maximum Withstanding Voltage Range T est Condition: CDF- AEC-Q100-002- “Human Body Model” Acceptance Criteria: “Normal Performance’ ±1000 V Other pins ±2000 V Symbol Parameter Value Unit R th j-amb Thermal Resistance Junction to Ambient 180 °C/W N Name Description 1 LBI Battery low voltage detector input. The internal threshold is set to 0.6V. The external threshold can be adjusted by using an external resistor divider. 2 COMP Error amplifier output. Compensate it with a 220pF capacitor 3 VFB Error amplifier input. The output voltage can be adjusted by using an external resistor divider connected to this pin (VFB = 0.6V). 4 GND Ground. 5 LX Switch node connection to the inductor. 6 VCC Input voltage. 7 SYNC This pin allows to select Low Noise/ Low Consumption Mode or to sychronize the device.

8 LBO

Battery low voltage detector output. If the voltage at the LBI pin drops below the internal thrshold, LBO goes low. The LBO is an open drain output. A pull_up resistor should be connected between the pin and the output voltage LBI COMP VFB GND 4L X VCC SYNC LBO8 D01IN1239A/mod

ELECTRICAL CHARACTERISTICS (TJ = 25°C, VCC = 3.6V unless otherwise specified) (*) Guaranteed by design Symbol Parameter Test Condition Min Typ Max Unit Vcc Operating input voltage After Turn On 2.7 5.5 V Vcc ON Turn On threshold 2.8 V Vcc OFF Turn Off threshold 2.65 V Vcc hys Hysteresis 150 mV R p High side Ron V cc = 3.6V , Ilx =100mA 240 m Ω R n Low side Ron V cc = 3.6V , Ilx =100mA 215 m Ω Ilim Peak current limit V cc = 3.6V 1.2 A Valley current limit V cc = 3.6V 1.4 A Vout Output voltage range 0.6 Vcc V fosc Oscillator frequency 600 KHz fsync Sync mode clock (*) 500 1400 KHz DC CHARACTERISTICS Iq Quiescent current (low noise mode) Vsync = 0V, no load, VFB > 0.6V 230 µA Quiescent current (low cunsumption mode) Vsync = Vcc, no load, VFB > 0.6V 25 µA Ish Shutdown current V cc < 2.7V , VFB > 0.6V 0.2 µA Ilx LX leakage current (*) V cc < 2.7V , VLX = Vcc 1 µA Vcc < 2.7V , VLX = 0V 1 µA ERROR AMPLIFIER CHARACTERISTICS Vfb Voltage feedback 0.593 0.6 0.607 V Ifb Feedback input current (*) V FB = 0.6V 25 nA SYNC/MODE FUNCTION V sync_H Sync mode threshold high 1.3 V Vsync_L Sync mode threshold low 0.5 V LB SECTION VLBI LBI Threshold 0.6 V VLBO LBO Logic Low I sink = 1mA, Vcc = 3.6V, VLBI < 0.6V 0.2 0.4 V ILK-LBO LBO Leakage Current (*) V LBO = 3.6V , Vcc = 3.6V, VLBI > 0.6V 50 nA PROTECTIONS HOVP Hard overvoltage threshold 10 %Vout

DIM. mm inch A 1.10 0.043 A1 0.050 0.150 0.002 0.006 b 0.250 0.400 0.010 0.016 c 0.130 0.230 0.005 0.009 e 0.650 0.026 L1 0.950 0.037 k 0˚ (min.) 6˚ (max.) aaa 0.100 0.004 Note: 1. D and F does not include mold flash or protrusions. Mold flash or potrusions shall not exceed 0.15mm (.006inch) per side. MSOP8 (Body 3mm)

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